Zero back pressure exhaust...
Turbo Mini Forums

After doing some more reading into the evacusump system I wanna run, i've found out that I need a (ideally) zero back pressure exhaust system.

At the mo, I have a 1 7/8" maniflow twin box system (the back box is 2 1/4") but i'm thinking this may present a problem with the bigger engine.

Would I be best going to 2 1/4" from the manifold back and ditching the centre box?

as its a turbo, bigger is better :) if you want as little backpressure as possible you also want straight through silencers. why do you need a low / no back pressure exhaust?

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

With a turbo you wont need two boxes - the turbo is a pretty good silencer.

When the uninformed look under my bonnet I tell them that I have a rotary silence which allegedly provides a little more performance.

Ah sorry guys, this is for my N/A motor.

If you read the first line of my post you'll see why I need one

fit the evacusump valve near the tail pipe if you really want less backpressure,

otherwisw i would not worry too much, thats what the anti reversion valve is there for,

carl

WWW.FORCE-RACING.CO.UK PLEASE CLICK HERE

I,m also fitting evacusump and recently was told that Vizard had abandoned the idea except for competition engines as it tended to suck oil out of the engine and could empty the sump.

Cant see why myself, if the breather is from the rocker cover and in any case its always possible to put a flow restrictor in if it sucks too hard (!!)

(I was told that the exhaust flow was sufficient to cause a massive extraction effect)

first off if this is on a turboed lump i dont think you'll get any extraction,

the evacusump works on the basis that there are pulses that leave negative pressures at certain times, sucking crank case fumes out, on a turbo I think the pulses will be to moshed and weak to have this effect.

I would just stick a "smog pump" on driven by the crank and pipe it into the exhaust.

For the second time LOL

I have it on my bike Owen

Shot with Canon PowerShot A1100 IS at 2010-02-10

Shot with Canon PowerShot A1100 IS at 2010-02-10

internationally known as "big" swede

whoops! missed that.

No worries mini13...


I recognise that bike!!!

Where did you get the evacusump kit from Marcus?

DR 650 ?
95 or the like ?
FCR ?

What swingarm arrangement is that ?

Sorry for the hijack ...

We ( I ) would really appreciate a build thread about your bike !

Rusty by nature

is this it in action?

THATS NIC ISNT IT !!! nic have you got a big glove and a small hard ball ?

Edited by robert on 11th Feb, 2010.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Where did you get the evacusump kit from Marcus? Ebay, $25 two kits (V8) looks like summits own kit, smells china:)

DR 650 ? DR800
95 or the like ? 95
FCR ? 2xmikuni rs flatslide 34:s

What swingarm arrangement is that ? SR 500 swing arm, (lil bit modified to locate springs further back, otherwise stock) SR shocks

Sorry for the hijack ...

We ( I ) would really appreciate a build thread about your bike ! Maybe i can sort something out

is this it in action? yep, thats the evac kicking in at full macarone, ha ha

internationally known as "big" swede

DR 650 / DR 800, sorry 'bout that

I spotted it was a pre DR SE generation but didn't see it had two carbs otherwise I would definitively have not mistaken !
(I used to own a Freewind wich is a 2 carb DR 650 SE and I quite liked it)

What about this setup, is it a full blastin' SR 500 with a proper engine or a vintaged DR ?
Is it for the show or some specific racing I had no idea about ?

Anyway, it does looks the nuts !

Rusty by nature

I dont run any silencers what so ever. Just a pipe to the back split off to look like a miglia

1/4 Mile 14.3secs 96Mph Terminal 10psi of boost.


Fibreglass Parts? - http://www.tdkracing.co.uk/
Split Rims? - http://www.force-racing.co.uk/

you should still be able to get a vacuum even if there is slight pressure in the exhasut as the 'evacusump' principle works on the venturi effect.

I found that anti backfire valve, I'll sort out the part number tomorrow. Its as big as the one shown in the pics above.

Thanks for that confirmation Sprocket.

Whats the purpose of this device?

1/4 Mile 14.3secs 96Mph Terminal 10psi of boost.


Fibreglass Parts? - http://www.tdkracing.co.uk/
Split Rims? - http://www.force-racing.co.uk/

10 more HP in the pub,lol

WWW.FORCE-RACING.CO.UK PLEASE CLICK HERE

Lol

1/4 Mile 14.3secs 96Mph Terminal 10psi of boost.


Fibreglass Parts? - http://www.tdkracing.co.uk/
Split Rims? - http://www.force-racing.co.uk/

My objective is to try to reduce or eliminate the oil leakage from the rear main bearing on my inline 1275.

There is only a labyrinth seal there which is pretty ineffective if there is any crankcase pressure so trying to reduce the pressure rather than just adding breathers seems like a good idea.

I dont follow the theory of reduced oil consumption which is normally dependent on the condition of the rings and valve guides -in fact, if I am extracting crankcase oil vapour it may even slightly increase oil consumption.

This is an acceptable trade-off for no oily mess on the workshop floor.